Abstract
Background:
Age-related changes in physiological parameters are crucial in understanding the health and performance of working dogs, particularly those in demanding roles such as military and law enforcement. However, limited research exists on how aging affects the hematological and biochemical health of these dogs.

Aim:
This study aims to characterize age-related variations in hematological and biochemical parameters in working Belgian Shepherd dogs to provide insights that could inform health management strategies for these animals.

Methods:
Blood samples were collected from 26 male Belgian Malinois working dogs, categorized into three age groups: adults (2-6 years), seniors (7-10 years), and geriatrics (11+ years). Comprehensive hematological and biochemical analyses were conducted. Analysis of complete blood count was performed for total 16 parameters: red blood cell, white blood cell, packed cell volume, hemoglobin, and platelet, neutrophil, basophil, leukocyte, monocyte, lymphocyte, and eosinophil counts. Mean cell volume (MCV), mean cell hemoglobin, mean corpuscular hemoglobin concentration, red cell distribution width, and mean platelet volume (MPV) were subsequently determined. The biochemistry parameters included glucose, creatinine, urea, blood urea nitrogen:creatinive ratio, phosphorus, calcium, sodium, potassium, Na:K ratio, chloride, total protein, albumin, globulin, albumin:globulin ratio, as well as alanine aminotransferase, alkaline phosphatase, gamma glutamyl transeferase, total cholesterol, amylase and lipase.

Results:
Significant age-related changes were observed in various parameters. Older dogs exhibited decreased creatinine and increased phosphorus and potassium levels, indicating potential changes in muscle mass, renal function, and electrolyte balance. Additionally, the albumin to globulin ratio decreased with age, reflecting shifts in protein synthesis and immune function.

Conclusion:
The study highlights important age-related variations in hematological and biochemical parameters in working Belgian Shepherd dogs. These findings emphasize the need for age-specific health management strategies to maintain the health, performance, and longevity of these dogs, thereby enhancing their effectiveness in critical service roles.

Key words: Age-related changes, Hematological parameters, Biochemical markers, Belgian Shepherd dogs, Working dogs